Molecular Probing For Early Detection Of Oral Cancers

AUTHORS :

Dr. Aditya Jayan, House Surgeon

NSVK Sri Venkateshwara Dental College & Hospital, Bangalore, Karnataka

Dr. Gaurav

BDS, SCADA (USA), MDS Oral Medicine & Maxillofacial Radiology

Asst Professor, Dept of Oral Medicine & Maxillofacial Radiology

NSVK Sri Venkateshwara Dental College & Hospital, Bangalore, Karnataka

INTRODUCTION:

Oral cancer, as all of us are aware, is one of the most significant human maladies in our history. The alarming epidemiological data of various cancers of the human body, including oral cancers, has been disheartening in the literature existing so far. It is estimated that there are more than three lakh cases of oral cancer reported worldwide in literature to claim numerous lives annually 1,2. This malady has been an enigma not only to the patients but also the professionals (oral surgeons, physicians and oncologists). Cancer is not a disease of a patient alone, but the entire family (physically, psychologically and socioeconomically).

Presently cancers are being diagnosed very late usually at the untreatable stages. This increases the morbidity and mortality rates bringing down the 5 year survival rate drastically 3,4. Hence in the present scenario an onus for early diagnosis, probably at the molecular or bio molecular level before genotypic conversion takes place, lays the preamble for combating this deadly disease.

The complexity and diversity of cancer etiology and various investigative procedures has posed many hurdles in meeting the challenges of early diagnosis of cancer thereby improving the prognosis. Amongst the many early diagnostic tools for the same, a newer biosensor technology has shown the potential to provide fast and accurate results in picking up these gene-conversions at the molecular level, thus enhancing the prognostic outcome. It has claimed a sensitivity and specificity of 100%.1,4,6,7 diagnosis of cancer thereby improving the prognosis.

Hence, “biosensors” are indeed a new wave in early stage cancer diagnostics, which could definitely herald a new era in the field of oral oncology diagnosis and treatment planning.

DIAGNOSTIC KIT & THE MODE OF WORKING OF BIOSENSORS:

The kit consists of a silicon or a photonic crystal mounted on a glass slide(Fig-1). The preamble lies in detection of bio molecules like proteins. A drop of blood is pooled onto the silicon or photonic crystal following which the protein content of the blood is extracted. This gets bound to the antibody dot present on the crystals thus exposing the entire panel of proteins on the screen. The proteins pertaining to oral cancer (IL-8, AFPs) are segregated or sorted out and a chemical solution with a fluorescent tag is added to it. If the protein contains antibodies, it will fluoresce on application of LASER thus demonstrating the presence of dysplasia or malignancy in the body. This procedure claims a 100% sensitivity because these bio molecules of onco proteins can be picked up very early in the processes of onco genesis.

PRINCIPLE & WORKING:

Biosensors work on the principle that the tumors or the cancerous cells elaborate specific onco proteins which can circulate through the bloodstream and can be picked up even at minute concentrations1,5,8. These onco proteins are characteristic and are called Biosensors. Biosensor devices are specially designed to detect biological entities by converting biomolecular signals into electrical signals which is further analyzed. This technology has the potential to provide fast and accurate detection which is reliable in imaging of cancerous cells, monitoring angiogenesis and cancer metastasis3,7,16.

Staining techniques and other visual aids have been used routinely as early diagnostic tools to pick up Potentially Malignant Disorders. The concept and technology is based on genetic and morphological changes i.e. changes which have already caused oncoconversion7,8.

In terms of onco conversion, biosensors prove to be the most significant of all.

CONCLUSION:

The development of biosensors is probably one of the most promising ways to develop highly sensitive, fast and economic methods of analysis in early detection of cancers.

In this regard, biosensors come up as the best weapons of choice in the future of fight against oral cancers.

REFERENCES:

1. Rasooly A, Jacobson J. Development of biosensors for cancer clinical testing. Biosens Bioelectron. 2006;21(10):1851–1858.
2. Hu Y. BRCA1, hormone, and tissue-specific tumor suppression. Int J Biol Sci. 2009;5(1):20–27.
3. Stevens RC, Soelber SD, Near S, Furono CE. 2008. Detection of cortisol in saliva with a flow-filtered portable surface plasmon resonance biosensor system. Analytical Chemistry 80:6747″6751.
4. Luo CX, Fu Q, Li H, Xu LP, Sun MH, Ouyang Q, Chen Y, Ji H. Lab on a Chip 2005;5(7):726–729.
5. Epstein JB, Scully C, Spinelli J. Toluidine blue and Lugol’s iodine application in the assessment of oral malignant disease and lesions at risk of malignancy. J Oral Pathol Med 1992;21(4):160-163.
6. Warnakulasuriya KA, Johnson NW. Sensitivity and specificity of OraScan (R) toluidine blue mouthrinse in the detection of oral cancer and precancer. J Oral Pathol Med 1996;25(3):97-103.
7. Epstein JB, Oakley C, Millner A, Emerton S, van der Meij E, Le N. The utility of toluidine blue application as a diagnostic aid in patients previously treated for upper oropharyngeal carcinoma. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;83(5):537-547
8. Ya-Wei C (2007b) Methylene blue as a diagnostic aid in the early detection of oral cancer and precancerous lesion. Br J Oral Maxillofac Surg 45:590–591
9. Michaell A Huber, Samer A Bsoul and Geza T Terezhalmy. Acetic acid wash and chemiluminescent illumination as an adjunct to conventional oral soft tissue examination for the detection of dysplasia: A pilot study. Quintessence Int.2004;35:378-84.
10. Camile S Faraha, Michael J McCulloughb. A pilot case control study on the efficacy of acetic acid wash and chemiluminescent illumination (ViziLite™) in the visualisation of oral mucosal white lesions. Oral oncology.2007;48:820-82.
11. Grodzinski P, Silver M, Molnar LK. Nanotechnology for cancer diagnostics: promises and challenges. Expert Rev Mol Diagn. 2006; 6(3):307–318.
12. Banerjee HN, Verma M. Use of nanotechnology for the development of novel cancer biomarkers. Expert Rev Mol Diagn. 2006;6(5):679–683.
13. Wong PN. In vivo toluidine blue staining for the detection of oral cancer and precancer. PNG Med J 1982;25:278–80.
14. Silverman S Jr, Migliorati C. Toluidine blue staining and early detection of oral precancerous and malignant lesions. Iowa Dent J 1992;78:15– 6.
15. Betz CS, Mehlmann M, Rick K, et al. Autofluorescence imaging and spectroscopy of normal and malignant mucosa in patients with head and neck cancer. Lasers Surg Med 1999;25:323–34.
16. Zargi M, Fajdiga I, Smid L. Autofluorescence imaging in the diagnosis of laryngeal cancer. Eur Arch Otorhinolaryngol 2000;257:17– 23.
17. Novo M, H¨uttmann G, Diddens H. Chemical instability of 5-aminolevulinic acid used in the fluorescence diagnosis of bladder tumours. J Photochem Photobiol B 1996;34:143– 8.